I had a pair of kribs. Great fish, good entertainment and easy. But someone told me not to put tetras (cardinal tetras) in the same tank, because these little fish are egg thieves.

I wouldn't suspect that cards would want to steal eggs from a female krib. Mother kribs are so territorial and protective that sometimes even dad has to go into other quarters until the fry are free swimming.

I would suspect that whoever passed that info on to you had their facts confused. If I were going to breed kribs in a small tank, say a 10g, I wouldn't put cardinals or any other fish in the tank for their own safety. In a larger tank, it would be a different story and there would most likely be enough room for cards or neons to live peacefully in the upper areas of the tank._________________Best,